         best-char     (apply max-key char-bits avail-chars) ]
     best-char ) )
 
-(defn make-guess-freq
-  "Generate the next guess letter, based on letter frequencies in the surviving words. "
-  [keep-words used-chars]
-  (let [
-    col-char-freqs  (to-freqs-by-col keep-words)
-    all-char-freqs    (apply merge-with + col-char-freqs)
-    avail-chars       (set/difference (set(keys all-char-freqs)) used-chars)
-      ; _ (println "avail-chars" avail-chars )
-    max-avail-char    (apply max-key all-char-freqs avail-chars ) 
-  ] max-avail-char ) )
-
 (defn make-clue
   "Generate a clue given the target word and a vec of guessed letters."
   [target-vec guesses-set]

      _ (assert (= keep-words ["abcd" "xbcd"] ))
    guessed-chars       #{ \b }
      _ (assert (= guessed-chars #{\b} ))
    new-guess           (make-guess-freq word-array guessed-chars)
      _ (assert (= new-guess \x ))
    guessed-chars       (conj guessed-chars new-guess)
      _ (assert (= guessed-chars #{\b \x} ))
    new-clue            (make-clue tgt-word guessed-chars)
      _ (assert (= new-clue [\x \b nil nil] ))
  ] )
)


    word-array          (to-word-array  curr-words)
      _ (assert (= word-array
                   [[\a \b \c \d] [\x \b \c \d] [\x \x \c \d] [\x \x \x \d]] ))

    tgt-word            [ \x  \b  \c  \d  ]
    clue                [ nil \b  nil nil ]
